Apparatus for fabricating three-dimensional paper-molded products with zero-draft angles

ABSTRACT

An apparatus for fabricating three-dimensional paper-molded products with zero-draft angles is disclosed herein, which comprises at least one conveying rail and at least three sets of mold assemblies for sequentially applying a pre-compression, a first thermo-compression and a second thermo-compression on each semi-finished product. The at least three sets of mold assemblies are collocated, in ascending order of their transversally cross-sectional concave widths, along the at least one conveying rail. By gradually compressing the semi-finished product in sequence of compression operations of the at least three sets of mold assemblies, a specific transversally cross-sectional width of the semi-finished product are gradually and transversally widened to finalize a formation of a three-dimensional paper-molded product having zero-draft angles, thereby enhancing a structural strength of the entire product, shortening its manufacturing time and saving its manufacturing cost.

FIELD OF THE INVENTION

The present invention relates to a technical field of fabricating three-dimensional paper-molded products, and more particularly, is related to an apparatus for fabricating three-dimensional paper-molded products with zero-draft angles.

BACKGROUND OF THE INVENTION

A common process of fabricating paper-molded products (or so-call “paper-molded products”) includes using paper slurries as a raw material, and employing a molding mold assembly to suction pulps from the raw material and then to compress the pulps in finalizing a specific finished shape of each paper-molded product. Such a finished product can be recycled and remanufactured for reuse which conforms to the current trend toward energy saving and carbon reduction, for environmental protection.

Nevertheless, while the molding mold assembly exerts an extruding-compression or a thermo-compression on each paper-molded product during the process of fabricating the paper-molded products, the molding mold assembly merely applies a single vertical-direction force, namely a downwardly extruding force, causing an uncompressed formation for lateral sidewalls of the paper-molded products, especially in its side edges, and therefore rendering the drawbacks as follows.

One is that a bottom plate and lateral sidewalls of the paper-molded products appear in an uneven density and/or different thicknesses. And, the other is that if the molding mold assembly is actuated in a releasing-mold manner, molds of the molding mold assembly should have inclined draft angles formed on side edges/bended locations thereof so as to easily release the paper-molded products from the corresponding molds. However, this result is why sidewalls/side-edges of the commonly-known paper-molded finished products are not always a right angle.

For the aforementioned drawbacks, a Taiwanese patent application No. 201711926 introduces a method for manufacturing a right-angled pulp product, which include screening a paper pulp to form a flat shape, pressing and heat-drying the flat paper pulp to make a paper product having a plurality of troughs in bended locations, taking out the paper product, cutting off burrs of the pulp product, coating the troughs, and bending adjacent plates at two sides of each troughs to make the pulp product having a right angle and a fixed shape.

However, although the aforementioned prior art might overcome the disadvantages, including unevenness of both density and thicknesses of the whole paper-molded products and non-right-angle bended locations of the paper-molded products, the aforementioned prior art has to adopt a lot of extra steps including cutting and adhesion steps for the plurality of troughs in bended locations of the paper slurry product. For a fabricating process, if the cutting and adhesion steps are implemented for many times, this would become complicated and cumbersomely, thereby wasting a huge amount of labor time and cost; furthermore, for the product, coating a large amount of adhesives onto its bended locations for adhesion into right angles would result the entirely structural strength weakened, especially in adhered locations.

Therefore, it is essential to provide an apparatus for fabricating three-dimensional paper-molded products, so as to solve the above-mentioned drawbacks of the prior arts.

SUMMARY OF THE INVENTION

In order to solve the aforementioned drawbacks of the prior arts, an objective of the present invention is to provide an apparatus for fabricating three-dimensional paper-molded products with zero-draft angles, which merely uses a plural sets of mold assemblies, each consisting of a pair of molds formed with right-angle side edges, to gradually shape each semi-finished product with right-angle side edges, in sequence of compression operations of the mold assemblies, without a need of extra using adhesives onto the bended locations for adhesion into right angles and without a need of a formation of inclined draft angles on the respective molds of the mold assemblies. Accordingly, the present invention is not only capable of enhancing a structural strength of the paper-molded product but also shortens its laboring time and saving its manufacturing cost.

To accomplish the aforementioned objectives, the present invention provides an apparatus for fabricating three-dimensional paper-molded products with zero-draft angles, which comprises at least one conveying rail, a paper slurry tank used for supplying a paper-molded material, at least three sets of mold assemblies, an absorbing unit and an ascending/descending mechanism.

Each of the at least three sets of mold assemblies consists of a male mold having a convex portion, and a female mold having a concave portion formed with a transversally cross-sectional concave width and with corresponding to said convex portion.

The absorbing unit is used to absorb a semi-finished product constructed of the paper-molded material, through the respective mold assemblies. The ascending/descending mechanism is used to convey the semi-finished product, among the respective mold assemblies, along the at least one conveying rail, wherein the mold assemblies are collocated in ascending order of their transversally cross-sectional concave widths and along an extended direction of the at least one conveying rail, and the mold assemblies respectively and sequentially apply a pre-compression, a first thermo-compression and a second thermo-compression on the semi-finished product conveyed along the at least one conveying rail, to gradually and transversally widen a specific transversally cross-sectional width of the semi-finished product in finalizing a formation of each of the three-dimensional paper-molded products having the zero-draft angles.

Preferably, the mold assemblies includes a first set of mold assembly, a second set of mold assembly and a third set of mold assembly, and The ascending order of the transversally cross-sectional concave widths of the mold assemblies is that the transversally cross-sectional concave width of the concave portion of the female mold of the second set of mold assembly is larger than the transversally cross-sectional concave width of the concave portion of the female mold of the first set of mold assembly, and the transversally cross-sectional concave width of the concave portion of the female mold of the third set of mold assembly is larger than the transversally cross-sectional concave width of the concave portion of the female mold of the second set of mold assembly.

Preferably, the apparatus for fabricating the three-dimensional paper-molded products with the zero-draft angles further comprises a cutting unit, connected to the at least one conveying rail and having a cutting mold assembly used to cut the semi-finished product.

Preferably, the male mold of each of the mold assemblies is formed with pathways extended through the convex portion and respectively communicated with the absorbing unit to reach said semi-finished product, the absorbing unit is used to absorb water vapor contained within the semi-finished product via the pathways and provide the male mold with a capability of grabbing the semi-finished product during the semi-finished product is conveyed.

Preferably, the absorbing unit is a vacuum pump.

Preferably, the apparatus for fabricating the three-dimensional paper-molded products with the zero-draft angles further comprises a fourth set of mold assembly collocated along the at least one conveying rail and used to apply a third thermo-compression on the semi-finished product, thereby increasing shaped times of the semi-finished product. In the other word, this can provide more diversified parameter configurations, which are beneficial to stabilize the process and raise the manufacturing quality.

A beneficial effect brought by the present invention is that compared with the prior arts, the apparatus for fabricating three-dimensional paper-molded products with zero-draft angles according to the present invention provides a formation of each of the paper-molded products which merely utilize a plural sets of mold assemblies for directly shaping each of the three-dimensional paper-molded products having zero-draft angles, without a need of extra using adhesives for adhesion into right angles on bended side edges of the product, and without a need of a formation of inclined draft angles on the molds so as to release the semi-finished products from the molds, thereby not only enhancing a structural strength of the entire product but also shortening its laboring time and its saving manufacturing cost.

DESCRIPTION OF THE DIAGRAMS

The above and other objects, features, and advantages of the invention will be better understood from the following detailed description thereof when it is considered in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a laterally cross-sectional diagram of an apparatus for fabricating three-dimensional paper-molded products with zero-draft angles, of a first preferred embodiment according to the present invention;

FIG. 2 illustrates a partially schematic diagram of said apparatus for fabricating three-dimensional paper-molded products shown in FIG. 1; and

FIG. 3 illustrates a laterally schematic diagram of another apparatus for fabricating three-dimensional paper-molded products with zero-draft angles, of a second preferred embodiment according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description of the embodiments is given by way of illustration with reference to the specific embodiments in which the invention may be practiced. The use of any directional term is used to describe and to understand the present invention and is not intended to limit the invention.

Please refer to FIG. 1 and FIG. 2, which respectively illustrate a laterally cross-sectional diagram and a partially schematic diagram of an apparatus for fabricating three-dimensional paper-molded products with zero-draft angles, of a first preferred embodiment according to the present invention. The apparatus comprises at least one conveying rail 1, a paper slurry tank 20 for supplying a paper-molded material 2, three sets of mold assemblies 5, 6, 7 collocated in sequence along the at least one conveying rail 1, an absorbing unit 10 and an ascending/descending mechanism 3, wherein the absorbing unit 10 can be realized as a vacuum pump. The absorbing unit 10 is configured to absorb each semi-finished product constructed of the paper-molded material 2, through the respective three sets of mold assemblies 5, 6, 7. The ascending/descending mechanism 3 is configured to further convey the semi-finished product absorbed by the absorbing unit 10, with accompanying either of molds of each of the mold assemblies 5, 6, 7, along the at least one conveying rail 1, among the three sets of mold assemblies 5, 6, 7. In this preferred embodiment, the three sets of mold assemblies 5, 6, 7 include a first set of mold assembly 5, a second set of mold assembly 6, and a third set of mold assembly 7, wherein each of the three sets of mold assemblies 5, 6, 7 is constructed of a male mold 51, 61, 71 and a female mold 52, 62, 72 correspondingly matched to the male mold 51, 61, 71. The male mold 51, 61, 71 has a convex portion 510, 610, 710 formed with a transversally cross-sectional convex width having right-angle side edges, and the female mold 52, 62, 72 has a concave portion 520, 620, 720 formed with a transversally cross-sectional concave width having right-angle side edges and with corresponding to the transversally cross-sectional convex width of the convex portion 510, 610, 710 of the male mold 51, 61, 71. The male mold 51, 61, 71 and the female mold 52, 62, 72 of each of the mold assemblies 5, 6, 7 are used to upwardly-and-downwardly compress the semi-finished product therebetween in each close-mold manner. In this preferred embodiment, the mold assemblies 5, 6, 7 are used to respectively apply a pre-compression, a first thermo-compression and a second thermo-compression on each semi-finished product conveyed along the at least one conveying rail, in sequences of gradual and respective compression operations of the mold assemblies of the fabricating process according to the present invention.

From the first set of mold assembly 5 to the third set of mold assembly 7 along an extended direction of the at least one conveying rail 1, the three sets of mold assemblies 5, 6, 7 are collocated in ascending order of different dimensions of their transversally cross-sectional concave widths. In this preferred embodiment, along the extended direction of the at least one conveying rail 1, the male molds 51, 61, 71 of said mold assemblies 5, 6, 7 are collocated in ascending order of their transversally cross-sectional convex widths, and the female mold 52, 62, 72 of said mold assemblies 5, 6, 7 are also collocated in ascending order of their transversally cross-sectional concave widths. It means that the transversally cross-sectional convex widths of the convex portions 510, 610, 710 of the male molds 51, 61, 71 of the mold assemblies 5, 6, 7 have different dimensions, and the transversally cross-sectional concave widths of the concave portions 520, 620, 720 of the female molds 52, 62, 72 of the mold assemblies 5, 6, 7 have different dimensions, wherein the transversally cross-sectional concave width ‘w2’ of the concave portion 620 of the female mold 62 of the second set of mold assembly 6 is larger than the transversally cross-sectional concave width ‘w1’ of the concave portion 520 of the female mold 52 of the first set of mold assembly 5, while the transversally cross-sectional concave width ‘w3’ of the concave portion 720 of the female mold 72 of the third set of mold assembly 7 is larger than the transversally cross-sectional concave width ‘w2’ of the concave portion 620 of the female mold 62 of the second set of mold assembly 6.

Besides, the male mold 51, 61, 71 of each of the mold assemblies 5, 6, 7 is formed a number of pathways (not shown), as presently known, extended through the male mold 51, 61, 71 from the convex portion 510, 610, 710 to its base portion communicated with the absorbing unit 10, for suctioning each of the semi-finished products onto an outer surface of the convex portion 510, whereby the absorbing unit 10 is not only able to exhaust water vapor contained within the semi-finished product but also provides the male molds 51, 61, 71 with a capability of suction-grabbing the semi-finished product via the pathways, for conveying the semi-finished product along the at least one conveying rail 1. Furthermore, to benefit implementations of the first and second thermo-compressions of the semi-finished product, the second set of mold assembly 6 and the third set of mold assembly 7 are respectively disposed with heating units 65, 75.

In practice operation, the ascending/descending mechanism 3 actuates the female mold 52 of the first set of mold assembly 5 to descend into the paper slurry tank 20, for dredging up a wet pulp 21, as an original semi-finished product constructed of the paper-molded material 2, from the paper slurry tank 20 onto an inner surface of the female mold 52. Then, the ascending/descending mechanism 3 actuates the female mold 52 of the first set of mold assembly 5 to ascend to reach a predetermined position. Then, by the ascending/descending mechanism 3, the male mold 51 of the first set of mold assembly 5 is actuated to downwardly move, along a vertical rail, to reach the predetermined position where to constitute a set of compression molds with the female mold 52, thereby applying a pre-compression on the wet pulp 21 constructed of the paper-molded material 2. That is, both the male mold 51 and the female mold 52 of the first set of mold assembly 5 are actuated in a close-mold manner to apply an extrusion-compressing force on the wet pulp 21 while the absorbing unit 10 vacuum-absorbs the wet pulp 21 via the pathways of the first set of mold assembly 5 so as to exhaust a part of water vapor and/or water moisture contained within the wet pulp 21, thereby forming a first semi-finished product 22 constructed of the paper-molded material 2, depending on an innermost contour of the concave portion 520 of the female mold 52.

Next, the male mold 51 of the first set of mold assembly 5 continuously absorbs the first semi-finished product 22 thereon by the absorbing unit 10 while ascending by actuation of the ascending/descending mechanism 3 for return to reach an initial position before the dredging-pulp operation starts. Next, the first semi-finished product 22 absorbed onto the male mold 51 of the first set of mold assembly 5 is horizontally moved toward the second set of mold assembly 6 along the at least one conveying rail 1 and then moved downwardly from a higher position where the at least one conveying rail 1 is located, to reach a lower position corresponding to the female mold 62 of the second set of mold assembly 6, by actuation of the ascending/descending mechanism 3, until the male mold 51 of the first set of mold assembly 5 descends to face the female mold 62 of the second set of mold assembly 6, thereby putting down the first semi-finished product 22 from the male mold 51 of the first set of mold assembly 5 to the female mold 62 of the second set of mold assembly 6, under a manner of stopping absorbing the first semi-finished product 22 from the male mold 51. After putting down the first semi-finished product 22, the male mold 51 of the first set of mold assembly 5 vertically and/or horizontally returns to reach an initial position on the at least one conveying rail 1, by actuation of the ascending/descending mechanism 3.

Next, in the second set of mold assembly 6, either or both of the male mold 61 and the female mold 62 are moved with relative to each other in a close-mold manner that applies an extrusion-compressing force on the first semi-finished product 22 while the absorbing unit 10 vacuum-absorbs a part of the water vapor and/or water moisture contained within the first semi-finished product 22 via the pathways of both the male mold 61 and the female mold 62, in coordination of using the heating units 65 of the second set of mold assembly 6 to synchronously heat as implementing the first thermo-compression, so as to greatly eliminate the water vapor and/or water moisture contained within the first semi-finished product 22. Accordingly, the first semi-finished product 22 is further dried in its molding depending on an innermost contour of the concave portion 620 of the female mold 62, thereby achieving a second semi-finished product 23 constructed of the paper-molded material 2. It needs to explain that, since the transversally cross-sectional concave width ‘w2’ of the concave portion 620 of the female mold 62 of the second set of mold assembly 6 is substantially larger than the transversally cross-sectional concave width ‘w1’ of the concave portion 520 of the female mold 52 of the first set of mold assembly 5, outer sidewalls of the first semi-finished product 22 should be laterally spaced at an interval t1 from inner sidewalls of the concave portion 620 of the female mold 62 of the second set of mold assembly 6 after the first semi-finished product 22 is put down within the concave portion 620 of the female mold 62 of the second set of mold assembly 6. The first semi-finished product 22 that is not completely dried yet still has an extensibility in its molding such that when the second set of mold assembly 6 is actuated in a close-mold manner, a specific transversally cross-sectional width of the first semi-finished product 22 is transversally widened by suffering the extrusion-compression of the male mold 61 of the second set of mold assembly 6 until the interval t1 thereof is eliminated to form a second semi-finished product 23 (as referring to FIG. 2) constructed of the paper-molded material 2. Next, the male mold 61 of the second set of mold assembly 6 absorbing the second semi-finished product 23 thereon by the absorbing unit 10 is horizontally moved along the at least one conveying rail 1 and then downwardly moved to reach a position corresponding to the female mold 72 of the third sets of mold assemblies 7, by actuation of the ascending/descending mechanism 3. Accordingly, the male mold 61 of the second set of mold assembly 6 descends to face the female mold 72 of the third set of mold assembly 7, thereby putting down the second semi-finished product 23 from the male mold 61 of the second set of mold assembly 6 onto the female mold 72 of the third sets of mold assemblies, under a manner of stopping absorbing the second semi-finished product 23 from the male mold 61. After putting down the second semi-finished product 23, the male mold 61 of the second set of mold assembly 6 vertically and/or horizontally returns to reach an initial position on the at least one conveying rail 1 by actuation of the ascending/descending mechanism 3.

Next, in the third set of mold assembly 7, either or both of the male mold 71 and the female mold 72 are moved with relative to each other in a close-mold manner that applies an extrusion-compressing force on the second semi-finished product 23 while the absorbing unit 10 vacuum-absorbs a part of water vapor and/or water moisture contained within the second semi-finished product 23 via the pathways of both of the male mold 71 and the female mold 72, in coordination of using the heating unit 75 of the third set of mold assembly 7 to synchronously heat as implementing the second thermo-compression, so as to greatly eliminate the rest water vapor and/or water moisture contained within the second semi-finished product 23. Accordingly, the second semi-finished product 23 is greatly dried in this molding depend on an innermost contour of the concave portion 720 of the female mold 72, thereby achieving a third semi-finished product 24 constructed of the paper-molded material 2. Since the transversally cross-sectional concave width ‘w3’ of the concave portion 720 of the female mold 72 of the third set of mold assembly 7 is substantially larger than the transversally cross-sectional concave width ‘w2’ of the concave portion 620 of the male mold 61 of the second set of mold assembly 6, outer sidewalls of the second semi-finished product 23 are laterally spaced at an interval t2 from inner sidewalls of the concave portion 720 of the female mold 72 of the third set of mold assembly 7 after the second semi-finished product 23 is put down within the concave portion 720 of the female mold 72 of the third set of mold assembly 7. The second semi-finished product 23 that is not completely dried still has an extensibility in its molding such that when the third set of mold assembly 7 is actuated in a close-mold manner, a specific transversally cross-sectional width of the second semi-finished product 23 is transversally widened by suffering the extrusion-compression of the male mold 71 of the third set of mold assembly 7 until the interval t2 thereof is eliminated to form the third semi-finished product 24 (as referring to FIG. 2), which is treated as a three-dimensional paper-molded product in this embodiment.

With divided operations of the plural sets of mold assemblies 5, 6, 7 according to the present invention, a specific transversally cross-sectional width of each of the semi-finished products 21, 22, 23 formed with right-angle side edges is gradually and transversally widened in sequence of compression operations from the first set of mold assembly 5 to the third set of mold assembly 7 along the at least one conveying rail 1, to finalize a formation of each of the three-dimensional paper-molded products 24 having the zero-draft angles, without a need of extra using adhesives for adhesion into right angles on bended side edges of the product 24, and without a need of a formation of inclined draft angles on the respective molds 51, 52, 61, 62, 71, 72, so as to release the semi-finished products 21, 22, 23, 24 from the respective molds 51, 52, 61, 62, 71, 72 formed with right-angle side edges, thereby not only enhancing a structural strength of the entire product 24 but also shortening its laboring time and its saving manufacturing cost.

Returning to FIG. 1, the apparatus for fabricating the three-dimensional paper-molded products with zero-draft angles according to the present invention further comprises a cutting unit 9 connected to the at least one conveying rail 1 and having a cutting mold assembly 90 used for trimming the third semi-finished product 24 constructed of the paper-molded material 2.

Please further refer to FIG. 3, which illustrates a laterally schematic diagram of another apparatus for fabricating three-dimensional paper-molded products with zero-draft angles of a second preferred embodiment according to the present invention, a difference of this second preferred embodiment from the first preferred embodiment is that an apparatus of this second preferred embodiment comprises four sets of mold assemblies 5, 6, 7, 8. The four sets of mold assemblies 5, 6, 7, 8 includes a first set of mold assembly 5, a second set of mold assembly 6, a third set of mold assembly 7, and a fourth set of mold assembly 8, wherein the three sets of mold assemblies 5, 6, 7 are substantially the same as ones collocated in the aforementioned first preferred embodiment, which respectively apply a pre-compression, a first thermo-compression, and a second thermo-compression on each of the semi-finished products. The fourth set of mold assembly 8 in the second preferred embodiment also has a heating unit for further providing the semi-finished product with a third thermo-compression. The four sets of mold assemblies 5, 6, 7, 8 are collocated in ascending order of their transversally cross-sectional concave widths along the at least one conveying rail 1 (as shown in FIG. 1); namely, the transversally cross-sectional concave widths of the concave portions 520, 620, 720, 820 of the female molds 52, 62, 72, 82 of the four sets of mold assemblies 5, 6, 7, 8 have different dimensions, wherein the transversally cross-sectional concave width ‘w2’ of the concave portion 620 of the female mold 62 of the second set of mold assembly 6 is substantially larger than the transversally cross-sectional concave width ‘w1’ of the concave portion 520 of the female mold 52 of the first set of mold assembly 5 while the transversally cross-sectional concave width ‘w3’ of the concave portion 720 of the female mold 72 of the third set of mold assembly 7 is substantially larger than the transversally cross-sectional concave width ‘w2’ of the concave portion 620 of the female mold 62 of the second set of mold assembly 6, and the transversally cross-sectional concave width ‘w4’ of the concave portion 820 of the female mold 82 of the fourth set of mold assembly 8 is substantially larger than the transversally cross-sectional concave width ‘w3’ of the concave portion 720 of the female mold 72 of the third set of mold assembly 7. In the method process, the second thermo-compression applied by the third set of mold assembly 7 merely exhausts a part of water vapor and/or water moisture contained within the third semi-finished product 24 such that the third semi-finished product 24 still has an extensibility in its molding. Thus, the fourth set of mold assembly 8 further applies the third thermo-compression to transversally widen a specific transversally cross-sectional width of the third semi-finished product 24 and greatly exhaust the rest water vapor and/or water moisture contained within the third semi-finished product 24, so as to completely dry the third semi-finished product 24 in molding a formation of a three-dimensional paper-molded product having zero-draft angles. By increasingly disposing the fourth set of mold assembly 8 in the present invention, the more shaped times of the semi-finished product are increased, the more diversified parameter configurations can be achieved (i.e. the respective set of molds used, different drying temperatures heated, and/or duty times allocated, for different working stages), which are beneficial to stabilize the process and raise the manufacturing quality. Understandingly, the second preferred embodiment provides the four sets of mold assemblies 5, 6, 7, 8 but therefore does not limit the amount of using mold assemblies, e.g. more than four sets of mold assemblies can also be implemented.

Thus, the apparatus for fabricating the three-dimensional paper-molded products with the zero-draft angles of the first preferred embodiment and the second preferred embodiment according to the present invention is capable of directly molding three-dimensional paper-molded product having zero-draft angles by gradual and respective compressions of the plural sets of mold assemblies, each consisting of a pair of molds formed with right-angle side edges, in sequence of compression operations of the mold assemblies, so as to step-to-step widen the specific transversally cross-sectional width of the semi-finished product, without a need of extra using adhesives for adhesion into the right angles and without a need of a formation of inclined draft angles on the respective molds so as to smoothly release the semi-finished products from the respective molds, thereby not only enhancing a structural strength of the product but also shortening its laboring time and saving its manufacturing cost.

As described above, although the present invention comprises been described with the preferred embodiments thereof, those skilled in the art will appreciate that various modifications, additions, and substitutions are possible without departing from the scope and the spirit of the invention. Accordingly, the scope of the present invention is defined only by reference to the claims. 

What is claimed is:
 1. An apparatus for fabricating three-dimensional paper-molded products with zero-draft angles, comprising: at least one conveying rail; a paper slurry tank, used for supplying a paper-molded material; at least three sets of mold assemblies, each consisting of a male mold having a convex portion, and a female mold having a concave portion formed with a transversally cross-sectional concave width and with corresponding to said convex portion; an absorbing unit, used to absorb a semi-finished product constructed of the paper-molded material, through the respective mold assemblies; and an ascending/descending mechanism, used to convey the semi-finished product among the respective mold assemblies, along the at least one conveying rail; wherein the mold assemblies are collocated in ascending order of their transversally cross-sectional concave widths and along an extended direction of the at least one conveying rail, and the mold assemblies respectively and sequentially apply a pre-compression, a first thermo-compression and a second thermo-compression on the semi-finished product conveyed along the at least one conveying rail, to gradually and transversally widen a specific transversally cross-sectional width of the semi-finished product in finalizing a formation of each of the three-dimensional paper-molded products having the zero-draft angles.
 2. The apparatus for fabricating the three-dimensional paper-molded products with the zero-draft angles as claimed in claim 1, wherein the mold assemblies includes a first set of mold assembly, a second set of mold assembly and a third set of mold assembly, and the ascending order of the transversally cross-sectional concave widths of the mold assemblies is that the transversally cross-sectional concave width of the concave portion of the female mold of the second set of mold assembly is larger than the transversally cross-sectional concave width of the concave portion of the female mold of the first set of mold assembly, and the transversally cross-sectional concave width of the concave portion of the female mold of the third set of mold assembly is larger than the transversally cross-sectional concave width of the concave portion of the female mold of the second set of mold assembly.
 3. The apparatus for fabricating the three-dimensional paper-molded products with the zero-draft angles as claimed in claim 1, further comprising a cutting unit, connected to the at least one conveying rail and having a cutting mold assembly used to cut the semi-finished product.
 4. The apparatus for fabricating the three-dimensional paper-molded products with the zero-draft angles as claimed in claim 1, wherein the male mold of each of the mold assemblies is formed with pathways extended through the convex portion and respectively communicated with the absorbing unit to reach said semi-finished product, the absorbing unit is used to absorb water vapor contained within the semi-finished product via the pathways and provide the male mold with a capability of grabbing the semi-finished product during the semi-finished product is conveyed.
 5. The apparatus for fabricating the three-dimensional paper-molded products with the zero-draft angles as claimed in claim 1, wherein the absorbing unit is a vacuum pump.
 6. The apparatus for fabricating the three-dimensional paper-molded products with the zero-draft angles as claimed in claim 1, further comprising a fourth set of mold assembly collocated along the at least one conveying rail and used to apply a third thermo-compression on the semi-finished product. 